Power lift



Jan. 26, 1943. M, H, wo'oDRUFF ETAL .l v2,309,152

I POWER LIFT Filed April 15.` 1959 Patented Jan. 26, 1943 POWER LIFT Moffitt H. Woodruff, Lubbock, and Everett W. Todd, Houston, Tex.

Application April 15, 1939, serial No. 268,028

(Cl. 19e- 139) 2 Claims.

This invention relates to a powei` lift and power take-off for tractors and comprises a continuation in part of our co-pending application filed September 18, 1935, and maturing in a Patent No. 2,155,177, issued April 18, 1939.

It is a primary object of the invention to provide a device of the class described comprising a simple, eiicient and economical construction which may be readily actuated by the power from the prime mover of a tractorfor raising and lowering implements connected thereto and also for imparting rotative power to other devices or implements.

Another object is to provide a tractor power lift construction which may be set in operation manually and which will be automatically stopped when the raising or lowering operation has been completed.

Still another object is to provide a power lift device for raising or lowering a tractor implement and including power take-off means for imparting rotative power to a tractor drawn or other device.

Another object is to provide a power lift and power take-off device for tractors, such device including an over-running clutch between the declutching mechanism and the driven device.

These and other objects will be apparent from the following description taken in connection with the drawing in which Fig. 1 is a vertical section thru a unit embodying the invention.

Fig. 2 is an elevational view showing therelation of the unit of Fig. 1 with the elements of a tractor with which the device is used.

The invention is generally illustrated in Fig. 2 of the drawing in combination with the tractor I having a drive housing 2 thru which the drive axle 3 passes and is driven by the tractor motor thru suitable gearing (not shown) to impart tractive effort to the wheels 4. The drive housing 2 is enlarged at 5 and encases suitable driving instrumentalities whereby power is im` parted to the power lift mechanism 6, shown in detail in Fig. 1.

It is to be noted that the lift mechanism 6 is secured to the drive housing 5 thru the flange l. The unit 6 may therefore be attached to or detached from the tractor I as desired.

The lift mechanism 6 comprises a housing I0 which bears the flange 1 at its forward end and includes an end wall II in which a drive shaft I 2 is journaled by means of anti-friction bearing I3 secured in place by means of retaining ring I 4 and cap screws I5. While such construction is preferred it to be understood that the shaft I2 may be integral with the tractor I and protrude therefrom into the housing I0.

Intermediate the ends of the housing I0 is a vertical wall 20 havingan aperture 2I in alignment with the drive shaft I2. A bearing 22 tting within the aperture 2l the forward end of a driven alignment with the drive shaft I2.

A collar construction 25 is detachably connected to the rear end of the housing I0 and includes a vertical portion 26 and a bearing 2l which serves as a rear support for the driven shaft 23. A worm 2'8 is fixed to the driven shaft 3 between the walls 20 and 26 by means of a key 29.

A transverse shaft 3U is mounted in the housing I0 in spaced relation with the driven shaft 23 and has a worm gear 3| fixed thereto. 'Ihe worm gear 3| meshes With the worm 28 and is therefore driven in the direction indicated by the arrow 32 when the driven shaft 23 is rotated in the direction indicated by the arrow 9.

The transverse shaft 30 extends outwardly thru the side wall of the housing I0 and is provided at one end with a crank to which may be suitably connected any device such as a tractor implement which is to be raised or lowered.

A clutch mechanism generally indicated as 40 is provided to connect and disconnect the drive shaft I2 with the driven shaft 23. This clutch mechanism comprises a clutch member 4I xed to the drive shaft I2 by means of pin 42. -A complementary clutch member 43 is mounted upon the forward end of the driven shaft23 and is provided with the groove 44 whereby the member is slidably but non-rotatably fixed to the driven shaft 2'3.

The clutch members 4I and 43 are counterbored at their adjacent ends to provide an annular space 45 to receive the shoulder 46 on the forward end of the shaft 23, a compression spring 41 surrounding the shaft 23 and engage the shoulder 46 and the clutch member 43 so that the clutch member will be restrained from movement under any tendency to vibrate when the clutch is released, and also to facilitate the movement of the clutch member 43 to released position by snap action as the jaws of the clutch members move from engaging position.

The clutch control mechanism comprises a throw-out rod 50 which slidably fits within openings in the upper portion of the member 25 and the wall 20. This rod bears a yoke 5I at its forward end which constantly engages within the groove 52 in the clutch member 43. A spring 53 surrounds the rod 50 and engages a collar 54 thereon. It is to be understood that this spring is considerably stronger than is the spring 4l and hence the clutch will be engaged whenever rotatably supports the spring 53 is permitted to move the throw-.out

rod 50 forwardly. A cam member 6B is also xed upon the transverse shaft 3G and is provided with spaced seats BI upon the camming surface. A follower 62 is mounted between yoke members 63 which are attached to the throw-out rod 5I) thru shaft 23 in coaxial a vertical extension SII. The yoke members 63 are constantly urged upwardly by means of spring 65 whereby the follower 62 is maintained in engagement with the cam 6d. Unless the yoke 63 is held downwardly by means of the arm. 'Iii connected to shaft 'I'l and foot pedal 'I2 exteriorly of the housing I0, the follower 62 will be engaged by one of the seats 6I and the clutch mechanismv foot pedal 'I2 to overcome the force exerted by the spring 65 and disengage the follower 62 from the seat ,6 I.

The rearward end of the driven shaft 23 is provided with a jaw clutch collar l which' engages a complementary collar It fixed to the forward end of a power take-olf shaft TI. The rear end of the shaft I'I is mounted in an antifriction bearing T3 secured in place by means of retaining collar lil. The forward end of this shaft is rotat-v ably mounted within the clutchl collar i5 by rn'eans of bearing Si). Spring El surrounds the power take-off shaft 'Il and maintains the clutch' members 'I5 and 'I in engagement.

The power take-off mechanismv just described may beY removed from the remainder of the unit 6, the rearward end of the housing Ill then being enclosed by means of a suitable cap h eld in place by the cap screws 2,4. If, however, this mechae nism is used" it serves the purpose of providing a power take-off for the transmission of power of rotation to an implement or other device to be driven by the tractor I.

When the power take-off mechanism is used, itis to. be understood that means (not shown) is provided for holding the yoke 63 depressed so that the clutch I0 remains engaged and power is uniformly supplied to the mechanism driven thru the unit S. It is also to be understood that the lifting arm on th'e transverse shaft 3i! is disconnected from the shaft or from the movement which would otherwise be lifted thereby.

Whenever it is desired to terminate the transmission of power thru the unit G the yoke 63 is released and the follower 62 is permitted to engage one of the seats 6I whereupon the clutch 40,

will bef disengaged.

It is apparent that the rotation of the shaft 23 must terminate as soon as the clutch is disengaged. There is a tendency for the rotating mechanism to continue until the rotational energy thereof has been dissipated. The clutch elements 'I5 and 'It constitute an over-running clutch whereby the shaft 23 may stop rotating as soon as the clutch40 is disengaged and the driven mechanism will stop as soon as its energy of rotation is dissipated.

The, operation of the disclosed construction is believed apparent from the foregoing description. By way of summary it may be stated that when it ijs desired that an implement be moved from an elevated to lowered position or vice-versa, it is only necessary in accordance with the invention to apply sucient pressure to the foot-pedal 12 to release the follower 62 from seat 6 I. There,-

lio

upon the clutch mechanism IW will become engaged by virtue of the pressure exerted by the spring 53. The mechanism will then be driven thru the drive shaft I2 until the follower 62 engages the succeeding seat SI so that the clutch d will be disengaged and the operation discontinued.

If, on the other hand, it is desired to drive rotative mechanism through the unit 6, connection is made thereto through the power take-olf shaft 'Il and the clutch 49 is constantly engaged by suitably holding the yoke 63 depressed so that declutching will not occur. v'vhen declutching is desired it is necessary only to permit the yoke 63 to move upwardly for engagementlwith one of the seats or camming surfaces 6I as already described.

What is claimed is:

1. A power lift for tractors comprising drive and driven shafts, clutch members on said shafts, one of said clutch members being axially shiftable to connect and disconnect the driven shaft to and from the drive shaft, a worm on the driven shaft, a transverse shaft, a worm gear onthe transverse shaft engaging said worm, camming means fixed to said transverse shaft and having spaced camming surfaces thereon, clutch releasing means attached to the shiftable clutch member and engageable and movable by one of the camming surfaces to move the clutch member and thereby to disconnect the connection between the drive and driven shafts, said clutch releasing means comprising a yoke engageable with the movable clutch member, a spring operably connected to urge the movable clutch member into engagement with the fixed clutch member, a shift member connected to said yoke and including a follower normally engaged by one of said camming surfaces whereby the shiftable clutch member is held in spaced relation with the othergof said members, and manually operable means for releasing the follower from engagement with said camming surface.V

2; A power lift for tractors comprising drive and driven shafts, clutch members on said shafts,

one of said clutch members being axially shiftable to connect andl disconnect the driven shaft to and from the drive shaft, a worm onV the driven shaft, means normally resiliently urging the clutch members apart, a worm gear on the transverse shaft engaging said worm, camming means xed to said transverse shaft and having spaced camming surfaces thereon, clutch releasing means attached to the shiftable clutch member and engageable and movable by oneA ofj the camming surfaces to move the clutch member and thereby to disconnect the connection between the drive and driven shafts, said clutch releasing means comprising a yoke engageable with the movable clutch member, a spring operably connected to` urge the movable clutch mem-ber into engagement with the xed clutch member, said spring being capable of overcoming the force exerted by said first mentionedA means,` ashift member connected to said yoke and includ-ing afollower normally engaged by one c f said cammingsurfaces whereby the shiftable clutch member is held in spaced relation with the other of said clutch members, and manually operable means for releasing the follower from engagement withv said camming surface.

MOFFHT H. WODRUFF; EvERE'l-T w. Tonio. 

